Dresden 2017 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 25: Poster: Nitrides
HL 25.3: Poster
Monday, March 20, 2017, 15:00–19:00, P2-OG2
Optical and magnetic studies of MBE-grown ferromagnetic CrSe and CrS layers in zincblende structure — •Johannes Röder1, Richard T Moug2, Kevin A Prior2, Dana Vieweg3, Hans-Albrecht Krug von Nidda3, Alois Loidl3, and Wolfram Heimbrodt1 — 1Department of Physics and Material Science Center, Philipps University, Marburg, Germany — 2Institute of Photonics and Quantum Sciences, SUPA, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh , United Kingdom — 3Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, Germany
Theoretical calculations predicted Chromium chalcogenides in the zinc blende (ZB) structure to be promising candidates for half-metallic spin-aligner at room temperature. Unfortunately, the thermodynamically stable phase of CrSe and CrS is the hexagonal NiAs-structure. Different approaches have been tested to stabilize the ZB state. Most promising were CrSe layers grown on GaAs substrates with either ZnSe or ZnSe/MgS as buffer layers and CrS-layers embedded between ZnMgS layers. All samples have been grown by MBE. We investigated the ferromagnetic properties and magnetic phase transitions and the respective optical properties of these films by temperature dependent SQUID and time resolved photoluminescence measurements. Ferromagnetic phase transitions have been found. The highest yet observed Curie temperature was at 255 K. Optical measurements revealed excitonic transitions of ZnSe, CrSe as well as the type-II CrSe-ZnSe interlayer transition.